Create new account: You can make a new account from 12 seed phases.
Derive from an account: You can make a new account from your existing account. The same seed phases are used to make another account.
Import account from pre-existing seed: If you are using other wallets such as Polkawallet and Fearless wallet, you can import your account to Polkadot.js by using the pre-existing seed phases.
Restore account from backup JSON file: Another way to restore an account is to use a JSON backup file.